Java Articles - Page 226 of 540

JTextArea is one of the most common Swing-based components. By default, it does not support text formatting such as bold, italics, or colored text inside a textarea. In this article, we will learn to display bold text inside the JTextArea in Java. What is a JTextArea? A JTextArea class can extend JTextComponent and allow a user to enter multiple lines of text inside it. A JTextArea can generate a CaretListener interface, which can listen to caret update events. Syntax The following is the syntax for JTextArea initialization: JTextArea textArea = new JTextArea(); Adding Bold Text Inside the JTextArea We ... Read More

In this article, we will learn about the importance of the JSeparator class in Java. In GUI programming, appearance is highly important in creating good and user-friendly Java programs. Java Swing provides the JSeparator class as a simple but effective means of accomplishing this. What is JSeparator? A JSeparator is a horizontal or vertical line or an empty area used to split the components. A class called JSeparator is used to paint a line in order to divide the components within a Layout. The simplest way to insert a separator into a menu or a toolbar is by invoking the ... Read More

JViewportA JViewport class defines the basic scrolling model and it is designed to support both logical scrolling and pixel-based scrolling.The viewport's child called the view is scrolled by calling JViewport.setViewPosition() method.A JViewport class supports logical scrolling, that is a kind of scrolling in which view coordinates are not pixels.To support a logical scrolling, JViewport defines a small set of methods that can be used to define the geometry of a viewport and a view. By default, these methods just report the pixel dimensions of the viewport and view.Exampleimport java.awt.*; import javax.swing.*; public class JViewportTest extends JFrame {    public JViewportTest() {       setTitle("JViewport Test"); ... Read More

In this article, we will learn about the differences between the paint() method and the repaint() method in Java. In the AWT and Swing frameworks, rendering graphical components is done in two different roles by the two methods paint() and repaint(). The paint() Method This method holds instructions to paint this component. In Java Swing, we can change the paintComponent() method instead of paint() method as paint calls paintBorder(), paintComponent() and paintChildren() methods. We cannot call this method directly instead we can call repaint(). Syntax The following is the syntax: public void paint(Graphics g) { // paint() method ... Read More

In this article, we will learn to catch a double click and enter key events for a JList in Java. We will be using Java Swing to detect double click and Enter key events on a JList. When we double click an item in the list or press "Enter" key after selecting an item, the selected item is displayed. What is a JList? A JList can extend the JComponent class, which allows us to choose either a single or multiple selections. A JList can generate a ListSelectionListener interface, and it includes one abstract method, valueChanged(). Below is the graphical representation ... Read More

The Font class in Java is responsible for setting screen fonts, which are mapped to characters of the language in specific regions. But a FontMetrics class is said to be a font metrics object that encapsulates the data about the rendering of a specific font on a particular screen. Font A Font class can be used to create an instance of a Font object to set the font for drawing text, labels, text fields, buttons, etc, and it can be specified by its name, style, and size. Syntax The following is the syntax for Font initialization: Font font = new ... Read More

In this article, we will learn to set the background color of a JPanel in Java. When designing GUIs in Swing, changing the background color of panels is important for creating visually appealing applications. What is a JPanel? A JPanel is a container, and it is an invisible component in Java. The FlowLayout is a default layout for a JPanel. We can add most of the components, like buttons, text fields, labels, tables, lists, trees, etc., into a JPanel. Syntax The following is the syntax for JPanel initialization: JPanel panel = new JPanel(); Methods The important methods of JPanel are: ... Read More

A JList is a component that can extend JComponent class used to display a list of objects that allows the user to select one or more items.There are three types of selection modes for a JList in JavaListSelectionModel.SINGLE_SELECTION: Only one list index can be selected at a time.ListSelectionModel.SINGLE_INTERVAL_SELECTION: Only one contiguous interval can be selected at a time.ListSelectionModel.MULTIPLE_INTERVAL_SELECTION: In this mode, there is no restriction on what can be selected. This is a default mode.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class JListSelectionModeTest extends JFrame implements ActionListener {    private JList list;    private DefaultListModel listModel;    public JListSelectionModeTest() {     ... Read More

The program uses a JLabel to hold a count label, a JTextField component to hold the number count, JButton component to create add, remove and reset buttons. When we click the add button, the count in the JTextField will get incremented by '1' and by clicking the remove button the count will be decremented by '1'. If we click the Reset button, it will reset the count to '0'.Exampleimport java.awt.*; import java.awt.event.*; import javax.swing.*; public class CounterTest extends JFrame implements ActionListener {    private JLabel label;    private JTextField text;    private JButton addBtn, removeBtn, resetBtn;    private int count;    public CounterTest() {       setTitle("Counter Test");   ... Read More

In this article, we will learn to set a border for JCheckBox in Java. JCheckBox is a Swing component that is commonly used in user interface selection. Although it includes a default appearance, we can customize its look by setting borders in order to have a good visual effect. What is a JCheckBox? A JCheckBox is a component that extends JToggleButton, and an object of JCheckBox represents an option that can be checked or unchecked. Syntax The following is the syntax for JCheckBox initialization: JCheckBox Checkbox_name = new JCheckBox(); If there are two or more options, then any ... Read More